Rumus Delphi

procedure TForm1.Button1Click(Sender: TObject);
begin
if edit1.text = '' then
begin
edit1.SetFocus;
end
else
if a.FindKey([edit1.text]) then
begin
showmessage('Data Sudah Terdaftar');
end
else
with a do
begin
append;
fieldbyname('nis').asstring := edit1.text;
fieldbyname('nama').asstring := edit2.text;
fieldbyname('ttl').asstring := edit3.text;
fieldbyname('alamat').asstring := edit4.text;
fieldbyname('kelas').asstring := edit5.text;
fieldbyname('jurusan').asstring := edit6.text;
post;
a.refresh;
end
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
a.edit;
a['nis'] := edit1.text;
a['nama'] := edit2.text;
a['ttl'] := edit3.text;
a['alamat'] := edit4.text;
a['kelas'] := edit5.text;
a['jurusan'] := edit6.text;
a.refresh;
end;




procedure TForm1.Button3Click(Sender: TObject);
begin
a.delete;
a.refresh;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
if MessageDlg('Apakah anda yakin ke form2 atau keluar aplikasi ?',
mtConfirmation, [mbYes, mbNo], 0) = mrYes then
begin
form2.show;
end
end;

procedure TForm1.Edit7KeyPress(Sender: TObject; var Key: Char);
begin
if key =#13 then
begin
if a.FindKey([edit7.text]) then
begin
edit1.Text := a['nis'];
edit2.Text := a['nama'];
edit3.Text := a['ttl'];
edit4.Text := a['alamat'];
edit5.Text := a['kelas'];
edit6.Text := a['jurusan'];
end
else
begin
showmessage('Data Tidak Terdaftar');
end
end
end;

end.




procedure TForm2.Edit8KeyPress(Sender: TObject; var Key: Char);
begin
if key =#13 then
begin
edit7.Text := floattostr(strtofloat(edit5.text)* strtofloat(edit6.text));
edit9.Text := floattostr(strtofloat(edit8.text)- strtofloat(edit7.text));


end
end;
procedure TForm2.FormActivate(Sender: TObject);
begin
combobox1.Text :='';
with a do
begin
a.first;
while not a.Eof do
begin
combobox1.items.Append(a.fieldvalues['nis']);
a.Next;
end
end
end;

procedure TForm2.ComboBox1Click(Sender: TObject);
begin
a.first;
if a.FindKey([combobox1.text]) then
if combobox1.text = a.fieldvalues['nis'] then
begin
edit1.text :=combobox1.text;
edit2.text :=a['nama'];
edit3.text :=a['kelas'];
edit4.text :=a['jurusan'];
end
end;

end.